Site assembled multi-story stair

ABSTRACT

A prefabricated multi-story, site assembled stair is disclosed in which the temporary supporting members are all confined within the stairwell and in which the platforms are pivotally mounted on the prefabricated stair unit for rocking movement between an unobstructed raised position to normal horizontal position to form the landing.

[ Dec. 23, 1975 ABSTRACT United States Patent 1191 Simmons et a].

[ SITE ASSEMBLED MULTI-STORY STAIR 3,788,018 1/1974 Simmons et al.

[75] Inventors: Smith H. Simmons; Otho A.

William, both of Largo; Arthur E. v Miller, Tampa, all of Fla. [73]Assignee: Metal Service Company, Inc.,

Primary ExaminerJ. Karl Bell Attorney, Agent, or Firm-McDougall, Hersh &Scott Clearwater, Fla.

1 7 5 .l 9 l 9 4 0 1 l 0 A5 0 N mm. D. FA 1] 21 22 [.I.

A prefabricated multi-story, site assembled stair is disclosed in whichthe temporary supporting members are all confined within the stairwelland in which the platforms are pivotally mounted on the prefabricatedstair unit for rocking movement between an unobstructed raised positionto normal horizontal position to form the landing.

References Cited UNITED STATES PATENTS 3,720,024Theisen................................. 52/185 5 Claims, 12 DrawingFigures may US. Patent Dec. 23, 1975 Sheet 1 of5 3,927,518

U.S. Patent Dec. 23, 1975 Sheet 2 of 5 3,927,518

FIG, 4

US. Patent 1166.23, 1975 Sheet4of5 3,927,518

U.S. Patent Dec. 23, 1975 Sheet 5 of5 3,927,518

SITE ASSEMBLED MULTI-STORY STAIR This invention relates to prefabricatedstairs for multi-story buildings adapted to be manufactured at a commonsite for efficiency in mass production and to be transported as anunassembled unit to a distant site for assembly and installation in theconstruction of multistory buildings, such as homes, apartments, motels,office or factory buildings.

It will be apparent that commercial success of such prefabricated,multi-story stairway units depends upon the ability to effect materialsavings in the cost of materials and assembly, and to minimize weight toenable economical handling and transportation of the unassembled units.Shipment in an'unassembled state enables economical transportation ofmultiple units on conventional transports from the manufacturing site tothe building construction site. Another advantage is the ability tostack. one unit onto another in building up the stairway as a sequentialfunction in advance of building construction whereby use can be made ofthe preinstalled stairway as a means for gaining access to upper floorlevels in advance of their construction.

In the latter connection, the prefabricated, multistory stair unit of.this invention is pre-installed in position of use in advance of theconstruction of the corresponding levels of the building'whereby thepre-installed stairs become available as a means for gaining access tothe upper floor levels by members of the building trades thereby toavoid the necessity to construct expensive scaffolding, temporaryladders, elevators or the like, while providing increased safety byreason of the greater stability and more space available with theprefabricated, pre-installed, multi-story stair unit of this invention.

As the floors are completed, including the masonry defining thestairwell, the structural elements of the prefabricated,prednstalledstair assembly are incorporated into the masonry and other structuralelements of the building permanently to incorporate themultistory,'pre-installed'unit in the stairwell of the building tobecome a permanent part thereof. It will be apparent that as thebuilding construction catches up withthe upper levels of the multi-storystair unit, additional units can be stacked one on top of the other torise above the current level of the building until the stairway risescontinuously to the ultimate height of the building. In existingconstruction of multi-story stair units, use is made of continuousstructural members for support In another system presently in use, stairruns and supporting masts are stacked into position as the buildingprogresses. This method does not provide access to the upper workinglevel until such level is in place and requires much more time forerection as erection crews must be brought to the stair location atleast twice per story, whereas our stair provides access to upper levelsas they are being worked on and two, three, four or more stories of ourprestacked stairs can be erected as a unit.

-It has been found that oftentimes the foundation or slab on which theprefabricated unit is pre-installed is not perfectly flat or level. As aresult, perfect vertical alignment of the stacked stair units isdifficult to achieve or to adjust, especially if the stairs have beenassembled and stacked but before they are incorporated as a permanentpart of the building. This often leads to instability of the stairs andthe need to make major reconstructions or repairs.

It is an object of this invention to provide prefabricated stair unitswhich can be assembled at the building site; which are capable ofeconomical production on a mass production basis to make available unitsat less cost at the construction site; which occupy minimum space andmake use of a minimum amount of material in the prefabricated unitthereby to enable easier handling of the unit and transportation thereofby conventional transports; which are further characterized by atemporary supporting system which is contained entirely within thestairwell and therefore are not required to be embedded in the masonrywalls with the resultant minimization of the amount of masonry work andelimination of unnecessary steel support parts; in which certainstructural elements such as the landing platform can be folded toprovide a prefabricated unit which occupies less space and in which lessof the structural elements are exposed to possible damage; in

of the elements in their prefabricated arrangement with the thought thatsuch continuous stair supports would be concealed within the masonry ofthe walls to tie the stairs into the-building as progress is made inbuilding construction. This imposes a number of limitations with respectto the dimensional characteristics of the prefabricated unit as relatedto the construction of the stairwell, but theneed to provide structuralsupports that: fit into the masonry operates undesirably to increase thebulk' as well as the amount .of material required in the prefabricatedunit with corresponding increase in weight as-well as the dimension andcost of the assembly. Since the support system remains for incorporationinto the walls, building costs are increased by reason of the need toconstruct the perimeters to embed the support members, including thecutting of masonry blocks toembed the support system.

which a minimum amount of bracing is necessary thereby to reduce thecost and weight of the prefabricated unit, which embodies means forself-alignment thereby to permit proper alignment of the installedprefabricated unit substantially independently of the surface orfoundation on which the unit is mounted.

These and other objects and advantages of this invention willhereinafter appear and for purposes of illustration, but not oflimitation, embodiments of the invention are shown in the accompanyingdrawings in which:

DESCRIPTION OF THE DRAWINGS FIG. 1 is an assembled side elevational viewof the prefabricated multi-story stair according to the presentinvention;

FIG. 2 is a plan view of the stair runs and temporary braces utilized infield construction of the present invention;

FIG. 3 is a plan view of the FIG. 2 components in their assembledpositions; 4 I

FIG. 4 is an end view along the lines 4-4 of FIG. 3;

FIG. 5 is a plan view of the header channels and newels utilized in theinvention;

FIG. 6 is a plan view of the components of FIG. 5 in their fieldassembled relationship;

FIG. 7 is an end view taken along the lines 7-7 of- FIG.6;-

FIG. 8 is a plan view of the additional stair runs and bracing membersrequired to complete the assembly of the present invention; i

FIG. 9 is a plan view of the completed assembly;

3 FIG. is a view taken along the lines l010 of FIG.

FIG. 11 is a plan view similar to FIG. 9 indicating the manner ofattachment of the platform; and

FIG. 12 is a view taken along the lines 12-12 of FIG. 11.

Referring now to the drawings, description will be made of aprefabricated three-story stair assembly embodying the features of thisinvention, but it will be understood that the concepts of this inventionmay equally be employed in one, two, four or other multistory units.Each assembled story section is formed with a platform 20, adapted toextend horizontally to provide a landing about midway between the floors22 and 24. Two lower stair runs 26 and 28 extend angularly downwardlyfrom about one-half of the inner edge of the platform to the floor belowand two upper runs of stairs 29 and 31 extend angularly upwardly fromthe other half portion of the same inner edge of the platform to thefloor above, with the upper stair runs 29 and 31 offset laterally fromthe lower runs.

Each stair run can be of conventional construction. For example, theconstruction shown and described in U. S. Pat. No. 3,788,018 assigned tothe present assignee may be utilized and such description isincorporated hereby.

The prefabricated multi-story stair unit is constructed with permanentsupports in the form of a pair of newels 40 and 42 represented in FIG. 1as a pair of vertically disposed parallel metal members such as steeltubular members, angle iron members or the like which are longitudinallyspaced by an amount corresponding to the horizontal distance covered byeach run of stairs and dimensioned to have a length corresponding to thetotal height of the prefabricated, multi-story stair unit. The newelsare connected by bolting, as will be described, to the adjacent stairruns to provide an assembled relationship therebetween.

At the approximate level where each upper and lower run of stairs meet,headers 50 and 52 are secured as by bolting to the vertical edgesdefining the ends of the runs to extend crosswise thereof. The headersare dimensioned to have a length greater than the combined width of thejoined stair sections to provide end portions which extend laterallybeyond the staircase for anchorage into the wall of the stairwell,thereby to anchor the stair assembly in the installed position in thebuilding.

The longitudinally spaced apart newels 40 and 42 preferably, though notnecessarily, can be allowed to remain as a permanent part of theprefabricated multistory stair unit, especially when prefabricated toreceive railings 60 and 62 which are mounted to run parallel with therun of stairs in vertically spaced apart relation thereto. The railingsare secured at their ends to vertically spaced portions of the newels.The railings, which do not form an essential part of the assembly, canbe installed as by attachment to the newels after installation of thestair unit or by mounting the rails on the walls of the stairwell afterthe masonry has been completed.

In the prefabricated unit of this invention, it is desirable to providetemporary vertical supports for the sections as a supplement to thesupport provided by the newels 40 and 42. Since such temporary supportsbecome superfluous after the headers 50 and 52 have been anchored intothe masonry walls, such vertical supports can be removed afterinstallation of the stair unit has been completed. By reason of theirtemporary nature, such additional supports are located within theframework of the stair unit so that the prefabricated multistory stairassembly can be constructed without external bracing of the typeheretofore required, or as a multi-story stair unit in which thetemporary supporting system is contained entirely within the frameworkand therefore free of the walls of the stairwell.

Such temporary supports are in the form of angle members 66 or otherelongate structural elements which extend vertically between theextremities of the stair runs. Support for the bottom run is provided byshort angle section 67 which extends vertically downward from the upperend of run 26. Such temporary bracing is secured to the stair runs bybolting through holes 65 and corresponding holes in the stair runs.After the described stair assembly has been installed and the headershave been anchored into the adjacent walls, the temporary bracing, aswell as the newels other than those on which the railings are mounted,can be removed to provide full access to the stairway.

The basic unit described, with all of the bracing confined within theframe members enables the prefabricated unit to fit entirely within thestairwell, represents an important feature of this invention. Theplatforms 20 are desirably supplied as separate elements to be mountedcrosswise of the inner ends of the upper and lower runs of stairsbetween the floors. As illustrated in FIG. 1, the platforms 20 arepivotally mounted to portions of the lower runs immediately above theheaders 50 prior to placing the assembled unit in the stairwell. Thisenables rocking movement of the platform between raised positionpermitting the assembly to fit within the stairwell and lowered positionof use.

Referring now to FIGS. 2-12, the prefabricated unassembled device isshown in a manner so as to illustrate the assembly steps required foron-site construction of the assembly. In the following description therequired component parts are indicated in FIGS. 2, 5 and 8,respectively, while the parts indicated in these figures are shown intheir assembled relationship to the entire structure in thecorresponding FIGS. 3, 6 and 9. These views and the accompanyingdescription are provided in recognition of the fact that one of theprincipal objects of this invention is to provide a prefabricated stairassembly which can be shipped in the unassembled condition and whenready for use, field assembled by semi-skilled personnel utilizing onlybolts.

In prior prefabricated stairs, such as in the referenced US. patent, thestair units could not be assembled at the job site but only at aproperly equipped factory. Thus, the assemblies were welded at thefactory and shipped three or four stories to a truckload. By utilizingthe unassembled configuration of this invention, as many as 24 floors ofstairs can be shipped on a single truck. Further, no intermediatewarehousing of stairs is necessary but the parts can be shipped directlyto a job site from the factory.

In order to begin assembly, a field stacking jig is first prepared. Thejig is indicated best in FIG. 4 wherein it comprises a pair of I-beams71 and 73. It will be recognized, of course, that the jig can be formedfrom any relatively level material, the only restraint being that thematerial should have a height of not less than 6 inches in order to keepthe stair unit raised off the ground, and further, the length of the jigshould not be less than the length of the stair unit. It will berecognized that the jig itself forms no part of the invention but ismerely used to facilitate the stair assembly,

Referring to FIG. 2, the first elements to be installed include thestair runs 29 and 31 and the temporary bracing 66. As indicated in FIG.3, these items are placed on the field jig 71, 73 with theproper spacingbetween the runs. The temporary braces are then bolted to the runs andpreferably, the bolting is made only finger-tight at this time. Thebolting is accomplished by aligning bolt holes in the runs withcorresponding holes 65 in the braces and then passing a threaded bolttherethrough to be secured by a nut. In a similar manner, as will bedescribed, the remaining components of the stair unit are field boltedto the stair flights.

Referring to FIG. 4, the end view of this first assembly step isillustrated. In order to secure the temporary braces to the stair runs,a single bolt is utilized at each end of the temporary braces.Additionally, a cross strut 69 is utilized to maintain the proper widthand add lateral rigidity.

Referring next to FIGS. 7, the second stage of assembly is illustrated.In this stage, a construction worker installs the permanent newels 40,42 as well as the header channels 50, 52. In order to increase theclarity of the drawings, the temporary bracing which was installed inthe first step is illustrated in FIG. 6 in dashed lines, while thepositions of the newels and headers areindicated by solid lines. Thenewels are bolted in the position shown and then the header channels 50,52 are bolted to the end plates of the stair runs 29, 31. Additionally,the header channels are butted against and connected to clip angles 53mounted on the newel posts to properly position them vertically. Again,the newels and the header channels are bolted fingertight only at thispoint in the construction. As indicated in FIG. 7, the headers 50, 52extend beyond the stair run 29, a short distance generally less than 6inches, which extension is adapted to be embedded in the masonry forproviding permanent anchoring. Similarly, the projections 63 on theheader 52 are provided for a like purpose.

Referring now to FIGS. 8-10, a third step in the construction of thefield assembled stair is illustrated. In this assembly step the stairruns 26, 28 are installed together with the corresponding temporarybracing elements 66. As indicated in FIG. 9, the stair runs 26, 28 arepositioned on top of the partially assembled structure supported on thenewels and bolted in place. At this juncture, all the hand-tightenedbolts for both sets of stair runs are fully tightened and all thetemporary bracing secured in place. The final step in the assembly ofthe stair is the attaching of the platforms 20.

As indicated in FIGS. 11 and 12, the platforms are attached to a flatbar portion of the header channel 50. The end of the platforms have acurved rodportion 91 which is inserted into an opening in the fiat barportion of header channel 50. The curvature of this rod permits theplatform 20, after attachment, to be placed in the position indicated indashed lines in FIG. 11. Thus, the platform is maintained flush againstthe newels and affixed thereto with chain, rope, or other means to holdit in place prior to installation of the unit in the stairwell. Ifutilized, the railings 60, 62 are next installed. Railings of the typeillustrated in FIG. 1 are installed by fastening the railings to thenewels preferably with self-tapping screws.

The platform 20 includes a corrugated steel deck 93 (FIG. 12-) fastenedonto the upper surface of spaced apart beams 95' and 97 and a header 99in the form of a steel channel or beam member which extends continuouslycrosswise beneath the outer end of the deck and beyond the platform.This header is embedded in the masonry walls for support of the platformin the installed position of use. The metal deck portion isconventionally covered with cement or paneling to provide the cross-overlanding between the opposite runs of stairs between the floors.

Means are provided temporarily to support the platforms when rocked totheir lowered positions during installation. The temporary supports arein the form of elongate rods 101 (FIG. 1) dimensioned to extendangularly between the outer end portion of the lowered platform 20 andthe lower portion of one of the temporary supports 66. Additional'details of the platform construction and deployment are contained inthe above referenced U.S. Pat. No. 3,788,018 incorporated hereby. I

The support for the lowermost platform 20 comprises a pair of laterallyspaced apart tubular members 103 fixed at their lower ends to a foot 102in the form of a crosswise extending angle iron which rests on the floorwhile the platform rests on the upper ends of the vertical rods 103 whenlowered to the position of use.

In practice, after the prefabricated multi-story stair unit has beeninstalled in its proper upright position at the desired location, thepivotally mounted platforms are released to enable them to rockgravitationally about their pivot to the lowered position. The angularsupporting rods 101 are braced at their lower ends against the verticalbrace 66 while the upper end is engaged in a socket on the underside ofthe platform. The platform comes to rest on the end of the tubularsupport member which thereafter is effective to retain the platform inthe desired horizontal position until the platform headers 99 becomeanchored in the'masonry of the adjacent walls. Thereafter, the tubularsupports 101 can be removed and the stairway finished by covering theplatforms landing material.

As previously pointed out, the prefabricated, multistory, stair ;unitscan be stacked one of the other to enable utilizationof suchprefabricated units throughout the height ofa multi-story building. 1

It has been found that oftentimes the floor or slab on which theprefabricated unit is installed may be uneven or sometimes theunit orbuilding settles after installation of the prefabricated stair assemblybut before it is incorporated into the building, with the result thatthe installed unit is not in proper vertical alignment for permanentattachment to the building. Various means which have heretofore beenemployed to effect alignment, such as shims, have been difficult toinstall and angular adustment thereby has been difficult to controlThus, a simple and efficient means by which the prefabricatedmulti-story stair unit of this invention can be adjusted at the time ofinstallation for effecting proper vertical alignment is desirable. Forthis purpose, the bottom angle irons 69 are provided with spacedopenings therein. The openings themselves can be threaded but it ispreferred to make use of a threaded nut member secured to the flangedportion in registry with each opening. Threadably engaged in each ofsaid threaded nut members or openings in an elongate bolt. Theprefabricated unit installed with a portion of the bolt extendingdownwardly beyond the opening so that the assembly will rest for supporton the throughextending portion of the bolts. When the prefabricatedunit has been installed, but before the headers are incorporatedpermanently into the masonry walls, angular adjustment of the unit iseffected by turning one or more of the individual bolts in one directionor the other depending upon whether or not it is desired to raise orlower the particular section of the assembly to compensate fordifferences in level or angle. The through-extending end portions of theleveling bolts are preferably provided with shoes to distribute theload, as described and illustrated in the above referenced patent.

The assembled prefabricated stair unit is stood upright on a pad orfoundation, as by means of a suitable gentry or crane, to position theprefabricated unit upright for installation. When properly positioned,the tradesmen can release the first platform which is then lowered ontothe lower tubular supports 103 until the platform comes to rest on thesupport. The platform at the next level is then released and is loweredonto the next pair of tubular support members. This is continued untilall of the platforms have been lowered to horizontal position to definethe landings.

Thereafter, the assembly is leveled by proper adjustment of the levelingbolts and the field assembled, prefabricated multi-story stair unit isready for permanent installation in the building by anchoring thelateral portions of the headers 50, 52 and 99 in the masonry or wallswhich define the stairwell. After installation and anchorage of theleaders, the temporary supports are removed to leave the installedstairway free of exposed bracing.

In the meantime, the prefabricated, pre-assembled and pre-installedmulti-story stair unit which extends vertically upwardly beyond thefloor level is available for use by the tradesmen for access toconstruct the upper level of the building whereby the multi-story stairunit enjoys considerable utility of great value even before the walls ofthe stairwell are built for permanent installation of the stairway intothe building.

As previously described, one unit can be stacked on another as thebuilding progresses whereby a continuous stairway is provided whichprojects upwardly beyond the current level of the building for use inconstruction of such upper levels or to gain access to such upper levelsas they are being built.

Thus, the stairs are set in position prior to the construction of themasonry walls thereby affording the various construction tradesimmediate access to all floor levels as the construction progresses.

lt will be apparent from the foregoing that the stairway assemblyembodying the features of this invention represents a unit formed of asupporting system which is confined entirely within the stairwell wallsthereby to reduce the amount of masonry work required for installationand minimize the amounts of steel structural supports required for theassembly. The temporary bracing members for the stair sections are allconfined within the stairwell to provide unblocked accessibility formounting the staircase. It will be understood that changes may be madein the details of construction, arrangement and operation withoutdeparting from the spirit of the invention, especially as'defined in thefollowing claims.

We claim:

1. A prefabricated stair unit shipped disassembled to a constructionsite for field assembly and installation on a field jig, comprising:

a. at least one pair of prefabricated stair flights;

b. headers for bolting to the ends of each flight of stairs anddimensioned to provide an anchoring portion for permanently anchoringsaid unit in an installed position;

c. newels field bolted to saidpair of stair flights and extendingvertically to provide permanent internal support for said unit;

. a platform for each pair of stair flights mounted by field bolting andmovable between a vertical position maintained during installation and ahorizontal position for permanent use as a landing; and

e. a plurality of temporary supports field bolted to said pair of stairflights during field assembly and removed after installation, saidsupports located wholly within the stair unit and extending verticallybetween the outer extremities thereof for temporarily supporting thestair flights in their assembled relation to permit permanentinstallation, said supports maintaining the flights in a laterallyspaced opposite running relation with the upper end of one flight andthe lower end of the other flight alongside one another at about midwaybetween the height spanned by the flights.

2. The prefabricated stair unit of claim 1 wherein said platform ismounted to the upper end of one flight at about midway between theheight .spanned by the flights by securing means including a curved rodintegral with said platform having threads thereon and openings in saidstair flight adapted to receive said curved rod for pivotally securingit thereto by bolting.

3. The prefabricated stair unit of claim 1 wherein said unit includesmeans for leveling said unit after assembly and before permanentinstallation.

4. The prefabricated stair unit of claim 1 in which the platformincludes a header joined to the underside of the platform adjacent theend farthest from the pivotal support and dimensioned to have a lengthgreater than the width of the platform to provide portions extendinglaterally beyond the platform for anchorage into a wall.

5. The prefabricated stair unit of claim 1 in which the platformcomprises a metal deck plate" and bracing members underlying the deckplate and socket openings in the outward extremities of the platform forreceipt of temporary bracing'members to support the platform whenlowered to horizontal position.

1. A prefabricated stair unit shipped disassembled to a constructionsite for field assembly and installation on a field jig, comprising: a.at least one pair of prefabricated stair flights; b. headers for boltingto the ends of each flight of stairs and dimensioned to provide ananchoring portion for permanently anchoring said unit in an installedposition; c. newels field bolted to said pair of stair flights andextending vertically to provide permanent internal support for saidunit; d. a platform for each pair of stair flights mounted by fieldbolting and movable between a vertical position maintained duringinstallation and a horizontal position for permanent use as a landing;and e. a plurality of temporary supports field bolted to said pair ofstair flights during field assembly and removed after installation, saidsupports located wholly within the stair unit and extending verticallybetween the outer extremities thereof for temporarily supporting thestair flights in their assembled relation to permit permanentinstallation, said supports maintaining the flights in a laterallyspaced opposite running relation with the upper end of one flight andthe lower end of the other flight alongside one another at about midwaybetween the height spanned by the flights.
 2. The prefabricated stairunit of claim 1 wherein said platform is mounted to the upper end of oneflight at about midway between the height spanned by the flights bysecuring means including a curved rod integral with said platform havingthreads thereon and openings in said stair flight adapted to receivesaid curved rod for pivotally securing it thereto by bolting.
 3. Theprefabricated stair unit of claim 1 wherein said unit includes means forleveling said unit after assembly and before permanent installation. 4.The prefabricated stair unit of claim 1 in which the platform includes aheader joined to the underside of the platform adjacent the end farthestfrom the pivotal support and dimensioned to have a length greater thanthe width of the platform to provide portions extending laterally beyondthe platform for anchorage into a wall.
 5. The prefabricated stair unitof claim 1 in which the platform comprises a metal deck plate andbracing members underlying the deck plate and socket openings in theoutward extremities of the platform for receipt of temporary bracingmembers to support the platform when lowered to horizontal position.